yading@10: /*
yading@10:  * SGI image decoder
yading@10:  * Todd Kirby <doubleshot@pacbell.net>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "libavutil/imgutils.h"
yading@10: #include "libavutil/avassert.h"
yading@10: #include "avcodec.h"
yading@10: #include "bytestream.h"
yading@10: #include "internal.h"
yading@10: #include "sgi.h"
yading@10: 
yading@10: typedef struct SgiState {
yading@10:     unsigned int width;
yading@10:     unsigned int height;
yading@10:     unsigned int depth;
yading@10:     unsigned int bytes_per_channel;
yading@10:     int linesize;
yading@10:     GetByteContext g;
yading@10: } SgiState;
yading@10: 
yading@10: /**
yading@10:  * Expand an RLE row into a channel.
yading@10:  * @param s the current image state
yading@10:  * @param out_buf Points to one line after the output buffer.
yading@10:  * @param out_end end of line in output buffer
yading@10:  * @param pixelstride pixel stride of input buffer
yading@10:  * @return size of output in bytes, -1 if buffer overflows
yading@10:  */
yading@10: static int expand_rle_row(SgiState *s, uint8_t *out_buf,
yading@10:                           uint8_t *out_end, int pixelstride)
yading@10: {
yading@10:     unsigned char pixel, count;
yading@10:     unsigned char *orig = out_buf;
yading@10: 
yading@10:     while (out_buf < out_end) {
yading@10:         if (bytestream2_get_bytes_left(&s->g) < 1)
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         pixel = bytestream2_get_byteu(&s->g);
yading@10:         if (!(count = (pixel & 0x7f))) {
yading@10:             break;
yading@10:         }
yading@10: 
yading@10:         /* Check for buffer overflow. */
yading@10:         if(out_buf + pixelstride * (count-1) >= out_end) return -1;
yading@10: 
yading@10:         if (pixel & 0x80) {
yading@10:             while (count--) {
yading@10:                 *out_buf = bytestream2_get_byte(&s->g);
yading@10:                 out_buf += pixelstride;
yading@10:             }
yading@10:         } else {
yading@10:             pixel = bytestream2_get_byte(&s->g);
yading@10: 
yading@10:             while (count--) {
yading@10:                 *out_buf = pixel;
yading@10:                 out_buf += pixelstride;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10:     return (out_buf - orig) / pixelstride;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Read a run length encoded SGI image.
yading@10:  * @param out_buf output buffer
yading@10:  * @param s the current image state
yading@10:  * @return 0 if no error, else return error number.
yading@10:  */
yading@10: static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
yading@10: {
yading@10:     uint8_t *dest_row;
yading@10:     unsigned int len = s->height * s->depth * 4;
yading@10:     GetByteContext g_table = s->g;
yading@10:     unsigned int y, z;
yading@10:     unsigned int start_offset;
yading@10: 
yading@10:     /* size of  RLE offset and length tables */
yading@10:     if (len * 2  > bytestream2_get_bytes_left(&s->g)) {
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     for (z = 0; z < s->depth; z++) {
yading@10:         dest_row = out_buf;
yading@10:         for (y = 0; y < s->height; y++) {
yading@10:             dest_row -= s->linesize;
yading@10:             start_offset = bytestream2_get_be32(&g_table);
yading@10:             bytestream2_seek(&s->g, start_offset, SEEK_SET);
yading@10:             if (expand_rle_row(s, dest_row + z, dest_row + s->width*s->depth,
yading@10:                                s->depth) != s->width) {
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Read an uncompressed SGI image.
yading@10:  * @param out_buf output buffer
yading@10:  * @param s the current image state
yading@10:  * @return 0 if read success, otherwise return -1.
yading@10:  */
yading@10: static int read_uncompressed_sgi(unsigned char* out_buf, SgiState *s)
yading@10: {
yading@10:     int x, y, z;
yading@10:     unsigned int offset = s->height * s->width * s->bytes_per_channel;
yading@10:     GetByteContext gp[4];
yading@10:     uint8_t *out_end;
yading@10: 
yading@10:     /* Test buffer size. */
yading@10:     if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     /* Create a reader for each plane */
yading@10:     for (z = 0; z < s->depth; z++) {
yading@10:         gp[z] = s->g;
yading@10:         bytestream2_skip(&gp[z], z * offset);
yading@10:     }
yading@10: 
yading@10:     for (y = s->height - 1; y >= 0; y--) {
yading@10:         out_end = out_buf + (y * s->linesize);
yading@10:         if (s->bytes_per_channel == 1) {
yading@10:             for (x = s->width; x > 0; x--)
yading@10:                 for (z = 0; z < s->depth; z++)
yading@10:                     *out_end++ = bytestream2_get_byteu(&gp[z]);
yading@10:         } else {
yading@10:             uint16_t *out16 = (uint16_t *)out_end;
yading@10:             for (x = s->width; x > 0; x--)
yading@10:                 for (z = 0; z < s->depth; z++)
yading@10:                     *out16++ = bytestream2_get_ne16u(&gp[z]);
yading@10:         }
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int decode_frame(AVCodecContext *avctx,
yading@10:                         void *data, int *got_frame,
yading@10:                         AVPacket *avpkt)
yading@10: {
yading@10:     SgiState *s = avctx->priv_data;
yading@10:     AVFrame *p = data;
yading@10:     unsigned int dimension, rle;
yading@10:     int ret = 0;
yading@10:     uint8_t *out_buf, *out_end;
yading@10: 
yading@10:     bytestream2_init(&s->g, avpkt->data, avpkt->size);
yading@10:     if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     /* Test for SGI magic. */
yading@10:     if (bytestream2_get_be16u(&s->g) != SGI_MAGIC) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     rle                  = bytestream2_get_byteu(&s->g);
yading@10:     s->bytes_per_channel = bytestream2_get_byteu(&s->g);
yading@10:     dimension            = bytestream2_get_be16u(&s->g);
yading@10:     s->width             = bytestream2_get_be16u(&s->g);
yading@10:     s->height            = bytestream2_get_be16u(&s->g);
yading@10:     s->depth             = bytestream2_get_be16u(&s->g);
yading@10: 
yading@10:     if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
yading@10:         return -1;
yading@10:     }
yading@10: 
yading@10:     /* Check for supported image dimensions. */
yading@10:     if (dimension != 2 && dimension != 3) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
yading@10:         return -1;
yading@10:     }
yading@10: 
yading@10:     if (s->depth == SGI_GRAYSCALE) {
yading@10:         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
yading@10:     } else if (s->depth == SGI_RGB) {
yading@10:         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;
yading@10:     } else if (s->depth == SGI_RGBA) {
yading@10:         avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGBA64BE : AV_PIX_FMT_RGBA;
yading@10:     } else {
yading@10:         av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
yading@10:         return -1;
yading@10:     }
yading@10: 
yading@10:     if (av_image_check_size(s->width, s->height, 0, avctx))
yading@10:         return -1;
yading@10:     avcodec_set_dimensions(avctx, s->width, s->height);
yading@10: 
yading@10:     if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     p->pict_type = AV_PICTURE_TYPE_I;
yading@10:     p->key_frame = 1;
yading@10:     out_buf = p->data[0];
yading@10: 
yading@10:     out_end = out_buf + p->linesize[0] * s->height;
yading@10: 
yading@10:     s->linesize = p->linesize[0];
yading@10: 
yading@10:     /* Skip header. */
yading@10:     bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
yading@10:     if (rle) {
yading@10:         ret = read_rle_sgi(out_end, s);
yading@10:     } else {
yading@10:         ret = read_uncompressed_sgi(out_buf, s);
yading@10:     }
yading@10: 
yading@10:     if (ret == 0) {
yading@10:         *got_frame = 1;
yading@10:         return avpkt->size;
yading@10:     } else {
yading@10:         return ret;
yading@10:     }
yading@10: }
yading@10: 
yading@10: AVCodec ff_sgi_decoder = {
yading@10:     .name           = "sgi",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_SGI,
yading@10:     .priv_data_size = sizeof(SgiState),
yading@10:     .decode         = decode_frame,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("SGI image"),
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10: };